Catheters are used in a wide variety of minimally-invasive or percutaneous medical procedures. For example, balloon catheters having drug coatings may be used to treat diseased target tissue, such as portions of blood vessels. Typically, for treatment of blood vessels, the balloon is inserted through a peripheral blood vessel and then guided via a catheter through the vascular system to the target intravascular site. However, as the balloon travels through the body, the flow of blood may wash away some of the drug coating, or the drug coating may otherwise become detached. This not only can result in an undesired loss of drug, but it can also result in drug being supplied to undesired parts of the body.
In certain drug delivery balloon catheters as have been proposed in the art, the surface of the balloon is coated with a coating containing the therapeutic agent to be delivered. When the balloon is expanded, the coating is pressed against the lumen wall, thereby delivering the drug. Such a system at times can be inefficient with respect to the delivery of the drug. Potential drawbacks that can be encountered with respect to drug delivery balloon catheters include not being able to deliver enough or the correct amount of the drug, not being able to deliver the drug quickly enough or in the desired time period, portions of the drug becoming dislodged during tracking of the catheter, and/or portions of the drug becoming dislodged during expansion of the balloon.
There is a continuing desire for improved catheter-based devices for drug delivery to a target site.